Temat: echo sounder - Katalog OPAC zbiorów

Skocz do pozycji: 1.

Tytuł:: Acoustic experiment on diel fish behaviour cycle performed in the Gotland Deep
Autorzy:: Orlowski, A.
Powiązania:: https://bibliotekanauki.pl/articles/332560.pdf
Data publikacji:: 2003
Wydawca:: Polskie Towarzystwo Akustyczne
Tematy:: acoustic experiment
Gotland Deep
echo sounder
Opis:: This paper describes the results of 24 h acoustic experiment based on three-dimensional measurements of the S; distribution of herring and sprat in the southern Baltic in October 2001. The experiment was based on a continuous (24h day) integration offish echoes using an EY500 echo sounder from a vessel with a constant speed of 8 knots, moving along the sides of a square equal to 4 n.mi., localized inside the specified area. Duration of the experiment was limited by deterioration of the weather conditions but nearly 300 ESDU samples were collected. These are correlated with values of coincident environmental factors: time, depth, water temperature, salinity and oxygen levels; estimated on the basis of survey data. Fish behaviour vs environmental factors is described by different macrosounding visualizations, statistical, and mathematical models. The purpose of the paper is to compare results of the experiment to the average characteristics of fish behaviour in the same basin, based on autumn studies over the period 1995-2001. General analysis was provided for the selected area of the Polish EEZ (south Gotland Deep), characterized by the greatest depth movements of fish diel migration. The most significant differences were found between fish migration pattern and diel stability of the acoustic response between these situations, specially during the sunset period.
Źródło:: Hydroacoustics; 2003, 6; 19-30
1642-1817
Pojawia się w:: Hydroacoustics
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Effect of in situ radiated noise of the platform used on shallow water area on echo sounder data in fisheries-acoustics
Autorzy:: Brehmer, P.
Guennegan, Y.
Arzelies, P.
Guillard, J.
Cheret, Y.
Duformentelle, P.
Colon, M.
Powiązania:: https://bibliotekanauki.pl/articles/332717.pdf
Data publikacji:: 2003
Wydawca:: Polskie Towarzystwo Akustyczne
Tematy:: in situ
echo sounder
fisheries
acoustics
Opis:: The shallow water area of the coastal fringes is important to take into consideration in fish stock assessment because a great part of the stock, especially for the small pelagic fish is distributed in this area (20). In shallow water research vessels are prohibited to navigation (usually <20m) and usually only small boats can be used. One of the main source error in acoustics fish sampling is due to the avoidance reaction generated by the three dimensional noise diagram emitted by the boat. In this paper we highlighted the importance of wind direction and strength in the noise diagram emitted by the boat under in situ condition. A comparison of the noise level of two boats (a Research Vessel and a Speedboat equipped of similar echo sounder) has been made before simultaneous records of echo sounder data: the speedboat is more silent as revealed by in situ hydrophone measurement and near the ICES recommendations. The observation of shoal echo sounder descriptors shows an avoidance reaction as expected more important for the noisier boat: there the schools avoid more the research vessel. The avoidance reaction is characterised by a deeper position of the fish school barycentre, in the water column, detected by the research vessel and a shoal minimum depth higher than for the speedboat. The effect of noise diagram difference is clear on the same shoal descriptors, the difference appears for the vertical position of the barycentre and minimum altitude.
Źródło:: Hydroacoustics; 2003, 6; 31-40
1642-1817
Pojawia się w:: Hydroacoustics
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Detection of Small Bottom Objects from Multibeam Echosounder Data
Autorzy:: Iwen, D.
Wąż, M.
Powiązania:: https://bibliotekanauki.pl/articles/320733.pdf
Data publikacji:: 2018
Wydawca:: Polskie Forum Nawigacyjne
Tematy:: Multibeam Echo sounder
bathymetric survey
bottom object
detection
Opis:: Multibeam Echo Sounder Systems (MBES) shallow water surveys provide capability not only acquiring bathymetric data useful for determining isobaths and mapping features on the seafloor which may be a hazard to navigation. They also allow detection of objects smaller or deeper than those required for the safety of seafaring and International Hydrography Organization (IHO) standards. In this article some of issues related to of efficient MBES shallow water surveys are stressed. Additionally a draft of post-processing techniques and result data format together with tools allowing extraction of bottom object from bathymetric data are presented.
Pomiary na płytkich wodach z użyciem systemu echosondy wielowiązkowej dają możliwości pozyskiwania danych batymetrycznych przydatnych do aproksymacji izobat, ale również mapowania cech dna morskiego mogących stanowić niebezpieczeństwo dla nawigacji. Ponadto pozwalają wykryć obiekty mniejsze lub położone głębiej niż wymaga tego standard Międzynarodowej Organizacji Hydrograficznej dla zapewnienia bezpiecznej żeglugi. W tym artykule zwrócono uwagę na pewne zagadnienia odnoszące się do wydajności pomiarów z użyciem echosondy wielowiązkowej na płytkich wodach. Ponadto przedstawiono sugestie odnośnie technik opracowania danych w trybie post-processingu wraz z dyskusją przydatności konkretnych formatów danych w przypadku posługiwania się wybranymi narzędziami dla wydzielenia obiektów dennych spośród danych batymetrycznych.
Źródło:: Annual of Navigation; 2018, 25; 219-232
1640-8632
Pojawia się w:: Annual of Navigation
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Method for the correlation coefficient estimation of the bottom echo signal in the shallow water application using interferometric echo sounder
Autorzy:: Grall, Piotr
Marszal, Jacek
Powiązania:: https://bibliotekanauki.pl/articles/2146649.pdf
Data publikacji:: 2021
Wydawca:: Politechnika Poznańska. Instytut Mechaniki Stosowanej
Tematy:: coherence estimation
multiphase echo sounder
sub-array processing
szacowanie koherencji
echosonda
Opis:: The article presents a new method for the assessment of bottom echo correlation coefficient in the presence of multiple echoes. Bottom correlation coefficient is a parameter that characterizes spatial properties of echo signal. Large variability of the bottom shape or properties (for example caused by the presence of bottom objects) and the presence of the acoustic shadow strongly influence the value of the correlation coefficient. There is a problem, however, in the proper determination of correlation coefficient of the bottom echo when more than one echo is present. In the shallow water application, the echoes coming to the hydroacoustic array from various directions influence the measured value of the correlation coefficient. The method proposed by the authors challenges this issue by applying a subarray processing based on the initial depth estimation. The article presents the preliminary research results and describes the limitations of the proposed method.
Źródło:: Vibrations in Physical Systems; 2021, 32, 1; art. no. 2021103
0860-6897
Pojawia się w:: Vibrations in Physical Systems
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: MEMS technology quality requirements as applied to multibeam echosounder
Autorzy:: Bikonis, K.
Demkowicz, J.
Powiązania:: https://bibliotekanauki.pl/articles/260431.pdf
Data publikacji:: 2018
Wydawca:: Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:: Inertial Measurements Unit
Multibeam Echo Sounder
attitude and heading reference system
motion reference unit
Opis:: Small, lightweight, power-efficient and low-cost microelectromechanical system (MEMS) inertial sensors and microcontrollers available in the market today help reduce the instability of Multibeam Sonars. Current MEMS inertial measurement units (IMUs) come in many shapes, sizes, and costs — depending on the application and performance required. Although MEMS inertial sensors offer affordable and appropriately scaled units, they are not currently capable of meeting all requirements for accurate and precise attitudes, due to their inherent measurement noise. The article presents the comparison of different MEMS technologies and their parameters regarding to the main application, namely Multibeam Echo Sounders (MBES). The quality of MEMS parameters is crucial for further MBES record-processing. The article presents the results of undertaken researches in that area, and these results are relatively positive for low-cost MEMS. The paper undertakes some vital aspect of using MEMS in the attitude and heading reference system (AHRS) context. The article presents a few aspects of MEMS gyro errors and their estimation process in the context of INS processing flow, as well as points out the main difficulties behind the INS when using a few top MEMS technologies.
Źródło:: Polish Maritime Research; 2018, 4; 59-64
1233-2585
Pojawia się w:: Polish Maritime Research
Dostawca treści:: Biblioteka Nauki

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